The present invention refers to a construction of a vacuum-breaking valve to be used in refrigeration appliances in general, such as refrigerators and freezers, in order to increase the internal pressure inside these appliances.
In refrigeration appliances, such as refrigerators and freezers which have, inside a cabinet G, at least one hermetically closed and thermally insulated compartment, inside which the temperature is lower than the temperature of the surrounding external environment, there is observed an undesired effect which tends to make difficult the opening of the door of said refrigeration appliance under certain circumstances.
This phenomenon is due to the decrease in the pressure of the air mass inside the refrigerated compartment, which is inherent to the decrease in temperature, producing a difference between the internal pressure, which is lower, and the external pressure, which is higher, mainly after the opening of the door and the subsequent closing thereof.
As a result, a force is produced on the door of the appliance acting to keep it closed and consequently making it difficult to open.
In order to overcome this problem and allow the users to open the door of the compartment of the refrigeration appliance with less effort, a device known as vacuum-breaking valve is used, whose function is to promote the equalization of the internal and external pressures. This valve is comprised, as illustrated in FIGS. 1 and 2 of the appended drawing, by a plastic piece in the form of a generally cylindrical and rectilinear tube 1, which crosses one of the walls of the cabinet G of the refrigeration appliance, in order to promote a fluid communication between the inside and the outside thereof and to allow, in certain occasions (notably when the internal pressure is lower than the external pressure), the external air to enter the refrigeration appliance, thus increasing the internal pressure until it becomes close to the external pressure of said refrigeration appliance. This tube 1 is open on its inner side and has on its outer side a sealing system consisting of a movable sphere 2, which is activated by gravity and is movable between a sealing position when inoperative, seated on a valve seat 3 of circular contour and sealing the air passage, and a spaced position when maintained suspended in a vertical portion of the tube 1, due to the difference between the external and internal pressures of cabinet G, thus liberating the air flow to the inside of said cabinet.
While reducing the effort required for opening the door, this solution usually allows, when air flows from the outside to the inside of the refrigeration appliance, the penetration of humidity (water vapor) dissolved in the air, which will freeze upon meeting the low temperatures inside the refrigeration appliance and which may obstruct the inner opening of the valve and impair its proper operation. To overcome this problem, the tubular body of the valve should be heated in order to prevent that the humidity coming from the outside freezes on the valve itself.
In a known solution, this heating is provided by an electric resistor (conducting wire, not illustrated) wound around the tubular body of the valve and which dissipates heat when subject to an electric current, promoting the desired heating of said valve. However, it has been observed that this solution, besides being expensive, since it increases the energetic consumption of the refrigeration appliance, may damage the valve body, which is usually in plastic material.
Thus, it is an object of the present invention to provide a vacuum-breaking valve, which reduces the effort required from the user to open the door of the refrigeration appliance, without the drawback of allowing the condensation of the humidity contained in the air that enters the valve, particularly in its inner end, and without modifying the energetic consumption of said refrigeration appliance.
A further objective of the present invention is to provide a vacuum-breaking valve, which is easy to obtain and mount in the refrigeration appliance. These and other objectives are achieved by a vacuum-breaking valve for refrigeration appliances including a cabinet closed by a respective door and refrigerated by a refrigeration system provided with a compressor, said valve comprising: a tubular body made of a thermally conductive material and mounted through one of the walls of the cabinet, in order to present an inner end, which is open to the inside of the cabinet, and an outer end, which is open to the outside of the cabinet; a valve seat mounted to the tubular body, in order to define a fluid communication between the inside and the outside of the cabinet; a sealing means mounted to the tubular body and which is constantly biased towards a closed position, in which it is seated on said valve seat, blocking the fluid communication between the inside and the outside said cabinet, and movable towards an open position, spaced from the valve seat and which is achieved when the pressure inside the cabinet is lower than the pressure outside said cabinet; and a heat collector, provided with a thermal radiation collecting surface and mounted around the tubular body adjacent to its outer end, so that said surface faces a heat source external to the cabinet.